This present invention has as its subject a lateral guidance device for a goods-handling system, as well as a goods-handling system using such a device. It is used especially in the area of continuous goods-handling systems, in particular on conveyor belts, roller conveyors, or chain conveyors for example, or indeed occasionally on laterally-gripping elevators, distributors, continuous dividers, turners, etc. . .
In general, in such continuous goods-handling systems, the products conveyed are guided laterally between guides of parallelepiped, circular or complex section.
These guides can be fixed. If they are fixed however, these systems provide no flexibility regarding the width between the guides, and therefore regarding the width of the products handled. In addition, it is necessary to modify the whole handling line in order to adjust this width on a change of the products handled.
In order to avoid such a long and costly operation, laterally adjustable guides have already been used in a manner to allow the guidance width to be altered. In this case, the adjustment can be manual, but this gives rise to the same problems as the modification mentioned above, or indeed can be achieved by pneumatic or electrical actuators.
In this last case of adjustment by actuators or jacks, whether pneumatic or electric, the size of the devices used is too great, and the technical implementation solutions prove to be costly, in particular in the curved parts of the conveyor system or in the case of conveying several products on several routes side by side.
There is therefore a need for a lateral guidance device for such goods-handling systems that allows the guidance width to be altered easily without the need to implement expensive and bulky technical solutions.
The purpose of the invention is therefore to overcome these drawbacks. To this end, according to a first aspect, the invention concerns a lateral guidance device for products moving on the conveyor track of a goods-handling system. The device is of the type that includes at least one hollow guide located along at least one part of the conveyor track and including at least two lateral profiles fitting together with each other. Each of these lateral profiles includes an inner face and a outer face, with at least one of these outer faces being a lateral external guidance face. The hollow guide also includes an upper face and a lower face. The guidance device of the invention is also equipped with means for the lateral adjustment of this lateral external guidance face, and is characterised in that it includes at least one expandable chamber housed in the hollow guide, and at least one means for supplying this expandable chamber with expansion fluid, so that the distance between the respective outer faces of profiles is adjustable as a function of the supplying of the chamber with expansion fluid between a minimum distance (chamber not expanded) and a maximum distance (chamber on maximum expansion).
The device also includes return means to facilitate the return of the lateral external faces of the profiles to the position of minimum distance between these lateral external faces, when the expandable chamber ceases to be supplied with fluid.
In an implementation variant, these return means include at least one spring connecting the two hollow guide profiles, with this spring being in the unstretched and uncompressed position when the chamber is not supplied with fluid and in the stretched or compressed position when the chamber is supplied with fluid.
In another implementation variant, possibly in combination with the previous one, the expandable chamber is affixed to at least one of the inner faces of the respective profiles.
The following implementation variants can also be considered, possibly in combination with the preceding ones:                the means for supplying the expandable chamber is a compressed-air means,        at least one of the lateral profiles is a metal profile,        at least one additional profile, possibly in plastic or indeed in metal, for the guidance of products of complex shape, is attached to the outer lateral guidance face,        the device includes several hollow guides assembled so as to form a hollow guide of considerable length, possibly with at least one of assembled hollow guides being curved, and possibly a separate expandable chamber for each of the assembled hollow guides.        
According to a second aspect, the invention concerns a goods-handling system, in particular of the conveyor type, which includes at least one frame structure and at least one conveyor track. The system of the invention also characteristically includes, on the conveyor track and fixed to the frame structure, at least one lateral guidance device according to the invention and as explained previously.
In an implementation variant, the guidance device is fixed to the system frame structure by at least one of the lateral hollow guide profiles.
In another implementation variant, possibly in combination with the first, the guidance device is fixed to the system frame structure by at least one of the upper and lower faces of the hollow guide.
Thus, the lateral guidance device and the goods-handling system according to the invention, are used advantageously to guide products on a conveyor track of variable width by simple adjustment of the quantity of fluid supplying the expandable chamber, and in particular facilitate adjustments at the curved parts of the conveyor track. The guidance device and the goods-handling system according to the invention also facilitate the conveyance of products on several routes side by side.
FIGS. 1a to 1d schematically show a first example of implementation of the device of the invention.